Cosmos 500: Object reference not set to an instance of an object

Question

Cosmos 500: Object reference not set to an instance of an object

Charlie LaMothe 26

A cosmos query results in the following error.

com.mongodb.MongoQueryException: Query failed with error code 1 and error message '[ActivityId=b00ed574-9fa8-4c64-bda4-51bcce5a1a53] Error=1, Details='Response status code does not indicate success: InternalServerError (500); Substatus: 0; ActivityId: 00000000-0000-0000-0000-000000000000; Reason: (Object reference not set to an instance of an object.);' on server badgr-pro-stg-azure-cosmosdb-southcentralus.mongo.cosmos.azure.com:10255

This appears to be a null pointer exception within Cosmos internals. Are there any known causes, that we could be triggering by our query, or troubleshooting suggestions? This query is known to work against Mongo.

Anurag Sharma 17,636 Reputation points

2021-05-17T06:04:58.993+00:00

Hi @Charlie LaMothe , welcome to Microsoft Q&A forum and sorry for the trouble you are facing.

Could you please provide the code snippet to fire the query and also couple of sample documents to repro the issue?
Yona Appletree 6 Reputation points

2021-05-18T23:27:39.33+00:00

Hi, I'm a coworker of @Charlie LaMothe who has been investigating this issue.

The problem occurs when sorting a cursor that contains just over 100 records, and the sort is done on an embedded value that is null.

I tried to include code here, but this comment form hangs when I try to submit the example. You can find a gist showing reproduction on a fresh database here: https://gist.github.com/Yona-Appletree/521fa7603ac6e4493eafbbb673613d7a
Anurag Sharma 17,636 Reputation points

2021-05-25T12:19:46.06+00:00

Sorry for delay in responding.

If possible, can you please attach the code file in text file format and same with the documents? Without the code it is really challenging to repro the issue.
Charlie LaMothe 26 Reputation points

2021-05-25T15:21:45.79+00:00

The reproduction steps were linked from Yona's comment. From a Mongo console:

use null-sort-bug
db.SortBug.createIndex({ "nested.value": 1 })
for (var i=1; i<200; i++) { db.SortBug.save({ nested: null }); try { db.SortBug.find().sort({ "nested.value": 1}).toArray(); } catch (e) { print("Failed after inserting " + i + " records."); throw e; } }
Anurag Sharma 17,636 Reputation points

2021-05-26T15:21:51.053+00:00

Thanks for the details provided. I am checking this issue internally with the team.
Anurag Sharma 17,636 Reputation points

2021-05-28T06:31:00.57+00:00

Hi, I am still in touch with product team and awaiting their response on this.
Ryś, Łukasz 1 Reputation point

2021-06-24T12:49:09.61+00:00

Hi, did you get any response regarding that issue? We are experiencing the same issue when sorting by nested field
Ryś, Łukasz 1 Reputation point

2021-06-24T12:50:09.237+00:00

Hi, did you get any response regarding that issue? We are experiencing the same issue when sorting with nested field